Well, it depends on what you are trying to achieve. You can export the originals + the ratings and edits to Photos, which allows you to continue editing and maintain full resolution. Or you can have Nitro generate a new file as you describe. But that will “burn in” the edits.
If your goal is to make a rendered image for Photos, then HEIF-10 is fine. If your original is RAW (as you state), then I would recommend a wide gamut color space, like Display P3 because 10-bit HEIF is fine for that (8-bit is not).